Cherneva, Radostina, Cherneva, Zheyna, Youroukova, Vania et al. · Biomedicines · 2025 · DOI
This study looked at 192 people who had COVID-19 to understand why some develop long-term fatigue and exercise problems. Researchers measured how well the heart adjusts during exercise and found that people with moderate-to-severe post-COVID symptoms had problems with their autonomic nervous system (the system that controls automatic body functions like heart rate). However, these nervous system problems didn't fully explain why patients had lower exercise capacity.
This study provides evidence that autonomic nervous system dysfunction is common in long-term post-COVID syndrome and may contribute to exercise intolerance. Understanding the mechanisms behind reduced fitness in PCS—and recognizing that multiple pathways may be involved—could help develop more targeted treatments for ME/CFS-like conditions and validate similar pathophysiology in primary ME/CFS.
The study does not prove that autonomic dysfunction directly causes low exercise capacity, since the two measures did not correlate statistically. The cross-sectional design cannot establish causation or determine whether autonomic dysfunction develops before or after symptom onset. The lack of correlation between objective autonomic measures and peak VO₂ suggests other mechanisms (mitochondrial, inflammatory, or neurological) also play important roles.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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